The Cup finals? Yeah. Multiply that by a couple. You’ve gotten this far. You’ve ignored the conference-championship trophy. You’ve dutifully recited your one-game-at-a-time mantra, but the truth is the truth: Win four more and …

And then, this: Sudden death. In the playoffs. In the finals. If you are a fan, you learn to breathe only when the puck is clear of your zone. If you are a player, your concentration triples: You don’t want to be the one with the giveaway. You don’t want a lapse to lead to a loss.

It is excruciating.

“You don’t want it to come down to the bounce of a puck,” Carl Hagelin said, “but when you have two evenly matched teams, you’re going to find yourself in overtime sometimes. And then that’s what it is …”

And then that’s what it was. Evenly matched? Put it this way: If the Kings and the Rangers give us five or six more games like this one, we’re going to be talking about hockey season well into football season, because that’s how terrific this opener was, how exciting, how bite-your-nails-and-shut-your-eyes intense it was.

And, of course, it came down to a bounce, to a stray puck off the stick of Dan Girardi, a stray puck that ultimately found its way onto the blade of Los Angeles’ Justin Williams, who flicked it past Henrik Lundqvist and launched the Kings to this 3-2 victory, to a 1-0 lead in the Cup finals.

“What we have to remember,” Martin St. Louis said, “was that this was only the first of four.”

But there was a reason St. Louis, and others inside the Rangers dressing room, felt compelled to remind us — and themselves — of these basic mathematics: because while that may well be so, while all the Kings really did last night was hold serve, and barely, as they skated off the ice it felt like more than that.

They are down 1-0 in this series.

Feels more like 1 ¹/₂ to 1. Feels that way because of how terrific the Rangers played early in seizing a 2-0 lead, in quieting the rabid Staples Center throng of 18,399, Hagelin scoring a second short-handed goal of these playoffs to go along with a pretty breakaway score from Benoit Pouliot.

Both teams wanted to believe they had destiny’s blessing heading into this showdown, because both had endured as exhausting a playoff gauntlet as the law allows. The Kings had survived 0-3 down to the Sharks in the first round, the Rangers overcame a 1-3 hole to the Penguins in the second.

Between them, they’d won five Game 7s. Four of them on the road.

“We feel good about where we are,” Derek Stepan said, “and they feel good about where they are, and that’s the way it should be.”

It’s just that the Kings are allowed to feel a little bit better this morning. Sixty-five minutes have shown us these two teams are every bit as evenly matched as we suspected, and if the Kings’ speed gives them a distinct advantage there, Lundqvist evens the ledger all by himself. The Rangers had a shot to steal this. And didn’t.

“We had some looks,” St. Louis said. “We had our chances.”

They still do, sure. They can still steal home-ice on Saturday, bring the series back to New York next week deadlocked, and see if the Kings can steal it back at a Madison Square Garden that promises to be as loud and as unfriendly as it has ever been for any sport, any event, in any era.

They lost a game Wednesday night, not the series.

But they also lost an opportunity, and knew it. The Tough night in the big town: The Yankees blew a four-run lead to the A’s, the Mets squandered an early three-run lead in Chicago to the Cubs, and the Rangers saw that two-goal cushion evaporate, and eventually skulked off the ice tagged with a loss that so easily could have gone the other way.

“First of four,” St. Louis said, and that’s the only way it pays for them to think. No matter how much it stings.